The invention relates to a drive device for rotating tools operating with oscillation superimposition exhibiting a drive housing, a carrier sleeve mounted rotatably in the drive housing, a drive shaft mounted rotatably in the carrier sleeve, a tool carrier to receive working tools and an oscillation-generating arrangement for producing the oscillation superimposition for the tool carrier.
In the drive devices of the kind in question with impact superimposition, activation of the impact impulse takes place by means of appropriate striking mechanisms, imbalance generators and, in particular, eccentric shafts, which carry freely rotating or driven working tools. Tools operating with impact superimposition are used in particular in mining, in tunnel construction and in road building, for example when hard rock or other mineral-bearing rock must be loosened, cut or worked in some other way. Impact superimposition permits the necessary pressing forces to be applied to the material intended for loosening or excavation to be reduced to as little as 1/10 of the pressing forces that are necessary without impact superimposition, which permits the use of lighter and smaller tools and machines and, at the same time, increases the extraction performance or daily headway of the tools.
Drive devices of the kind in question for tools on which impacts are superimposed are previously disclosed in EP 329 915 A1 and EP 455 994 B1. The drive devices of the kind in question each comprise a carrier sleeve that is rotatably mounted and is driven by a carrier sleeve drive with an eccentrically arranged internal bore, in which a shaft is rigidly connected to the tool carrier, which shaft is designated in the prior art as an eccentric shaft. The carrier sleeve is provided with counterweights for the dynamic balancing of the drive device, and the eccentric shaft is driven by means of a second drive, which can consist of a separate drive or a reduction drive. In a reduction drive, the speed ratio between the speed of the eccentric shaft and the speed of the carrier sleeve is fixed; in drive devices with a separate drive for the eccentric shaft, the speed ratio is variable within limits. The offset of the eccentric shaft in the carrier sleeve can be 5 mm, for example, and the speed ratio of the faster-rotating eccentric shaft to the more slowly-rotating carrier sleeve can be in the order of 30:1, so that the working tools mounted on the tool carrier strike the material or rock to be mined or worked with a large number of radial impacts. The loosening or mining performance achieved in the case of the tools with impact superimposition of the kind in question is already many times higher than in conventional drive devices without impact superimposition.
However, the considerable vibrations that are introduced into the drive housing and tool housing, the imbalance masses that are required in particular for dynamic balancing, and the service life of the seals and bearings for the eccentric shaft and the carrier sleeve, continue to be problematical in eccentric-induced drive devices with impact superimposition of the kind in question.